Recent experimental results on new all gas-phase chemical generation of atomic iodine via atomic fluorine for a Chemical Oxygen-Iodine Laser (COIL) are presented. Advantages of this method are emphasized in comparison with the conventional use of molecular iodine as a precursor of atomic iodine for lasing. Fluorine atoms are produced by fast reaction of molecular fluorine with nitrogen oxide and then react with hydrogen iodide to atomic iodine. Reaction conditions and the most convenient experimental arrangements were searched for their application in the supersonic COIL. An inevitable instrument used in this investigation was the optical Iodine Scan Diagnostics (ISD) of generated atomic iodine, based on the tunable diode probe laser. Concentration of atomic iodine was mapped by this method in the reactor at different experimental configurations, pressure and concentration of reactants. This research supported by mathematical modeling revealed that, the best arrangement would be generating atomic iodine in a separate reactor and injecting it into the singlet oxygen flow in the COIL.